High silica/alumina ratio faujasite type NaY

ABSTRACT

A sodium Y type faujasite having a high silica/alumina ratio is obtained by lowering the active soda content below the conventionally employed levels. This is done by adding an acid and/or an aluminum salt solution such as an aluminum sulfate solution to the sodium silicate in the zeolite synthesis slurry. Alternatively, the desired alumina and silica starting materials can be supplied in part by using an aluminum salt gelled mother liquor such as an alum gelled mother liquor. This permits the use of less reactants which are high in soda such as sodium silicate and sodium aluminate which in turn reduces the amount of soda present. The addition of these soda removers or the use of low soda reactants permits the production of NaY having a silica/alumina ratio of 5.0 and higher. These Y zeolites have a high degree of crystallinity as measured by an NMR sharpness index defined herein and they have an absence of occluded silica. The final product can be ion exchanged to a low level of Na 2  O with rare earth or other metal cations or ammonium ions, to make a more thermally and steam stable zeolitic promoter for catalysts for treating petroleum fractions than can be made from conventional sodium Y.

This is a continuation, of application Ser. No. 453,604, filed Dec. 27,1982, now abandoned.

FIELD OF THE INVENTION

This invention relates to the production of a Y-type zeolite having ahigh silica to alumina ratio and to the resulting unique zeoliteobtained.

DESCRIPTION OF THE PREVIOUSLY PUBLISHED ART

The Breck U.S. Pat. No. 3,130,007 is the basic patent on Zeolite Y andit defines the zeolite in terms of moles of oxides as

    0.9±0.2 Na.sub.2 O: Al.sub.2 O.sub.3 : w SiO.sub.2 : x H.sub.2 O

where w is a value greater than 3 up to about 6 and x may be a value ofup to about 9. The disclosed use for Zeolite Y is as an adsorbent.

Breck discusses two types of silica sources. When the major source ofsilica is a lower cost silica source such as sodium silicate, silica gelor silicic acid, the zeolite Y composition prepared usually hassilica/alumina (SiO₂ /Al₂ O₃) molar ratios ranging from greater than 3up to about 3.9. Examples are given in Tables III and IV. The lowestamount of soda used is in Range 5. By multiplying the lowest ratio ofNa₂ O to Al₂ O₃ (which is 0.6) by the lowest SiO₂ /Al₂ O₃ ratio of 8,the lowest possible Na₂ O content is 4.8 moles which is above line A inFIG. 1 to be discussed below.

When it is desired to have zeolite Y product compositions havingsilica/alumina molar ratios above about 3.9, then Breck employs as thepreferable major source of silica more expensive silica sources such asaqueous colloidal silica sols and the reactive amorphous solid silicas.Since these colloidal silica sols and reactive amorphous solid silicasare expensive materials as compared to sodium silicate, Breck does notprovide any teaching as to how to make high silica Y zeolite from lowercost reactants.

Breck also requires a first digestion at ambient or room temperature.The criticality of this cold aging for all the production processes isshown in Table V.

The Esso Great Britain Pat. No. 1,044,983 discloses making type Yzeolites having a silica to alumina ratio of 3 to 7 in which thereactants have low ratios of soda to silica and water to silica. Likethe Breck patent, the preferred silica source and the material used inall of the examples which are claimed to yield 5.5.6.8 SiO₂ /Al₂ O₃ratio in a well-crystallized NaY form is a silica sol which is anexpensive material.

The McDaniel et al U.S. Pat. No. 3,808,326 discloses tne use or seeds ornucleation cen having an average size below about 0.1 micron to produceType Y zeolites. In Example II the zeolite particles are stated topossess a silica to alumina ratio of about 5.0 to 6.0, but no individualvalues are listed. The SiO₂ to Al₂ O₃ ratios vary from 9.5 to 14.5 andthe amount of Na₂ O added is listed with the amount in each case beinggreater than the amount em in the present invention.

The Maher et al U.S. Pat. No. 3,671,191 discloses the preparation ofhigh silica synthetic faujasite by using seeds and a silica to aluminareactant ratio of about 16:1. At this preferred 16:1 silica to aluminasynthesis ratio the Na₂ O to alumina ratio shown in the Example is 6.6.This is identified as point G in the figure. Among the products producedis one having a ratio of 5.2 in Example 2 and 5.4 in Example 3.

The Elliott et al. U.S. Pat. No. 3,639,099 discloses producing afaujasite having a silica to alumina ratio greater than 4 by usingseeds. The improvement in this patent was to use a lower ratio of silicato alumina. A range of 8-12 SiO₂ to 1 Al₂ O₃ is disclosed with apreferred silica to alumina ratio in the reaction slurry of about 9:1.In that case the preferred reactant mixture has 3.5±0.4 Na₂ O for eachAl₂ O₃. The lowest level at a 9.1 silica to alumina ratio would be 3.1moles of Na₂ O. This point is identified as point F on the figure. Amongthe products made from a 10 to 1 ratio in Table 1 the lowest free Na₂ Oused was 3.5 and it produced a zeolite with a SiO₂ /Al₂ O₃ rario of only5.47.

The Whittam et al. U.S. Pat. No. 4,016,246 discloses the preparation ofzeolite Y having a silica to alumina molar ratio of greater than 3 up toabout 6.2. The method requires the use of an "active" sodiummetasilicate hydrate which is distinguishable from conventional sodiummetasilicates. This unique hydrate is produced by three methodsdescribed in the patent. Since this starting raw material is difficultto obtain because it requires special manufacturing techniques, it wouldappear that Whittam's method is also expensive to carry out.

The Vaughan et al. U.S. Pat. No. 4,178,352 discloses a synthesis of TypeY zeolite using a minimum of excess reactants. There is a genericstatement that the resulting zeolites can have a silica to alumina ratioof from about 4 to 5.5. However, the highest product ratio shown in theexamp is in Example 6 at a ratio of 5.1. The final reactant mixtureshave for each mole of Al₂ O₃ from 4 to 7.5 moles of SiO₂ and from 1.2 to3 Na₂ O. Most of the examples use reactant solutions where the silica toalumina ratio is 6 to 1 with 1.8 or 1.9 moles of Na₂ O. Point E in theFigure represents this technique where the silica to alumina mole ratiois 6 and there is 1.8 moles of Na₂ O for one mole of alumina.

The McDaniel U.S. Pat. No. 3,574,538 discloses using kaolin and in thepreferred embodiment metakaolin and sodium silicate in the form ofwaterglass to prepare faujasite materials having a silica to aluminaratio in excess of 4.5 from inexpensive raw materials. In the examples,products are made with the highest silica to alumina ratios of 5.90 and5.95. However, in industrial practice it is difficult to obtain kaolinand/or metakaolin that meet the desired chemical and physical propertieswhich optimize this process.

The Wilson Great Britain Pat. No. 1,431,944 discloses making acrystalline alumino-silicate zeolite having a silica-to-alumina moleratio in the range of 5.5 to 8.0. The method requires a series ofsequential steps for addition of the reactants. First, a faujasiteprecursor solution is formed and heated. Then, a sodium silicatesolution is added to increase the SiO₂ /Al₂ O₃ molar ratio. Next, as acritical step, an aqueous aluminum chloride solution is added to form agel slurry. Additional steps require heating, removing the gel from theslurry and adding further water to the gel with further heating topromote crystallization. The Wilson method does not relate to asynthesis procedure in which all of the reactants are essentially mixedtogether at the same time.

OBJECTS OF THE INVENTION

It is an object of this invention to produce a Y type zeolite having ahigh silica to alumina ratio of greater than 5.0.

It is a further object to produce a Y type zeolite having a high silicato alumina ratio, a high degree of crystallinity and an absence ofoccluded silica.

It is a further object of this invention to obtain a high silica Y typezeolite that is made from a source of alumina other than metakaolin orkaolin.

It is a further object of this invention to obtain a high silica Y typezeolite which can be used for catalytic purposes by employinginexpensive silica sources such as sodium silicate, silica gel orsilicic acid.

It is a further object to lower the active soda content in the reactionmixture to obtain a high silica Y type zeolite.

It is a further object to use an alum gelled mother liquor from aprevious synthesis as a starting material when lowering the active sodacontent to make a high silica Y zeolite.

These and other objects will become apparent as the description of theinvention proceeds.

SUMMARY OF THE INVENTION

High silica/alumina sodium Y type faujasite, HSAY, is produced bycarefully controlling the active soda content to a level below theconventionally employed amounts. The Y type faujasite is made from asource of alumina other than metakaolin or kaolin while the source ofsilica is an inexpensive source such as sodium silicate, silica gel,silicic acid or mixtures thereof. The soda content can be reduced by oneof two different techniques or a combination of the two. The firstinvolves adding a controller of active soda such as an acid and/or analuminum salt solution obtained from aluminum and an acid which reducesthe amount of active sodium in the zeolite synthesis slurry. Preferredmaterials are a dilute acid or a dilute aluminum sulfate solution. Theother technique involves using as a starting reactant a combinationsource of reactive silica and alumina which is low in active soda. Thiscan be used in conjunction with the individual source of silica andsource of alumina discussed above. A preferred combination source is aprevious mother liquor which has been treated with an aluminum salt toobtain an aluminum salt gelled mother liquor which is low in soda. Apreferred aluminum salt for this embodiment is aluminum sulfate which isalso known as alum.

By lowering the soda level, it is possible to produce unique, wellcrystallized NaY zeolites with a silca/alumina ratio of 5.0 and higherand especially at levels of 5.8 and higher. These unique highsilica/alumina products can also be ion-exchanged with rare earth orammonium cations to even lower levels of Na₂ O to produce a morethermally and steam stable zeolitic promoter for petroleum crackingcatalysts, petroleum hydrocracking catalysts, etc.

The Y type faujasites made by this process have a high degree ofcrystallinity. When these materials are studied by magic angle spinningnuclear magnetic resonance (m.a.s.n.m.r.) as discussed more fully infra,the peaks for the Si[lAl] and Si [0Al] are sharper than comparablecommercial samples. By expressing the sharpness relative to the Si[2Al]peak and multiplying by ten, a sharpness index, S.I., is obtained. TheS.I. for the Si[1Al] peak is at least 6 and preferably at least 7 whilethe S.I. for the Si[0Al] peak is at least about 2.2 and preferably atleast 2.5.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a graph of slurry compositions for producing Y faujasiteproducts in terms of ratios of Na₂ O and SiO₂ to Al₂ O₃.

FIG. 2 is the deconvoluted MAS NMR spectra for the high silica Y zeoliteaccording to the present invention and for commercial NaY.

FIG. 3 is a graph of SiO₂ /Al₂ O₃ ratio versus unit cell length for highsilica to alumina ratio faujasite type NaY.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The high silica/alumina sodium Y faujasites are made from sources ofalumina, silica, soda, seeds or nucleation centers, and a furtherreactant which permits a reduced active soda concentration to be presentin the reaction mixture.

The more preferred sources of the alumina can be either aluminatrihydrate, alumina monohydrate, a sodium aluminate solution, or analuminum sulfate (alum) solution. Other possible alumina sources couldbe alumina gel, aluminum hydroxide, aluminum chloride, aluminum nitrateor other salts of aluminum and acids. It is particularly desired not touse kaolin or metakaolin because in industrial practice it is difficultto obtain these two materials in a form that meets the desired chemicaland physical properties which optimize this process.

The preferred silica sources are inexpensive sources such as sodiumsilicate, silica gel, silicic acid or mixtures of these materials. It isparticularly desired for industrial application not to use the moreexpensive sources of silica such as aqueous colloidal silica sols or themore expensive forms of reactive amorphous solid silicas. Anotherpossible silica source is an alum gelled mother liquor to be discussedmore below.

The preferred source of soda is obtained from the sodium salt form ofthe compounds used to supply the silica and alumina, namely sodiumsilicate and sodium aluminate. Other possible soda sources are sodiumhydroxide and sodium carbonate although it must be remembered that thegoal of this invention is to reduce the amount of soda in the reactionmixture.

Seeds or nucleation centers can be the conventional Y zeolite seedmaterial or the mother liquor from the production of zeolites A, X or Yor alum gelled mother liquors. One preferred method of making the seedsis set forth in the McDaniel et al. U.S. Pat. No. 3,808,326 and isdescribed in Example 1 below.

The further reactant which permits a reduced active soda concentrationto be present in the reaction mixture can be added in one of two formsor a combination of the two. In the first form the material isconsidered a controller of active soda since it will react with theexcess active soda to bind it up so that it does not adversely affectthe synthesis of the high silica Y zeolite. Examples of materials whichcontrol this active soda concentration are acids, salts obtained fromreacting aluminum with an acid, and mixtures of these two materials. Theacid is preferably added in the dilute form and a preferred acid issulfuric acid. In the preferred embodiment these added controllers ofactive soda are added at the time of mixing of the slurry or they areadded within about 3 hours of the time that the slurry has been heatedto the most effective results.

The other form of the further reactant is to provide a combinationsource of reactive silica and alumina which is low in active soda. Thiscan be done by adding an aluminum salt to the silica containing motherliquor from a previous production to precipitate a silica/aluminahydrogel which is low in active soda. Examples of aluminum salts includealuminum sulfate, aluminum chloride, aluminum nitrate or mixturesthereof. Aluminum sulfate (alum) is the preferred salt. A preferredexample of this recycle technique is disclosed in the Elliott U.S. Pat.No. 4,164,551 where alum, which is aluminum sulfate, is added to thefiltered mother liquor to precipitate a silica/alumina hydrogel. Thishydrogel is referred to as AGML or alum gelled mother liquor and it orother aluminum salt gelled mother liquors can be used directly as astarting material when making the high silica faujasite according to thepresent invention.

According to this invention, the active soda content is to be reducedbelow the conventionally employed levels. Referring to FIG. 1, line Aillustrates the conventional formulations that produce a NaY faujasitehavin 5.0 SiO₂ to Al₂ O₃ ratio. For a reaction slurry at point G with 16moles of SiO₂ for every mole of Al₂ O₃ it has been traditional to havethe Na₂ O: Al₂ O₃ ratio at about 6.6. For a reaction slurry at point Fwith 9 moles of SiO₂ for each mole of Al₂ O₃, the Na₂ O: Al₂ O₃ ratiohas its lowest value at about 3.1 while for a reaction slurry at point Ewith 6 moles of SiO₂ for each mole of Al₂ O₃, the Na₂ O: Al₂ O₃ ratio isabout 1.7. Thus line A is based on at least the following points forratios in the synthesis slurry

    ______________________________________                                        SiO.sub.2 :Al.sub.2 O.sub.3                                                                 Na.sub.2 O:Al.sub.2 O.sub.3                                     Ratio         Ratio                                                           ______________________________________                                        16:1          6.6:1                                                           9:1           3.1:1                                                           6:1           1.8:1                                                           ______________________________________                                    

According to the present invention the soda levels are reduced to levelsbelow line A by the addition of a controller of active soda such as anacid and/or a salt of aluminum and an acid. This salt can be added as asolution. The preferred forms of the acid or salt are dilute solutionsand a preferred form of the salt is a dilute aluminum sulfate (alum)solution. In the more preferred embodiments the active soda content islowered down to the levels shown in line B of the figure where for areaction slurry with 16 moles of SiO₂ for each Al₂ O₃, the Na₂ O: Al₂ O₃ratio will be about 5.0 and for a reaction slurry with 9 moles of SiO₂for each Al₂ O₃, the Na₂ O: Al₂ O₃ ratio be about 2.4. Using thisstarting composition, NaY faujasites are obtained having a 5.8-6.0 SiO₂to Al₂ O₃ ratio. Thus line B is based on at least the following pointsfor ratios in the synthesis slurry

    ______________________________________                                        SiO.sub.2 :Al.sub.2 O.sub.3                                                                 Na.sub.2 O:Al.sub.2 O.sub.3                                     Ratio         Ratio                                                           ______________________________________                                        16:1          5.0                                                              9:1          2.4                                                             ______________________________________                                    

When adding the materials to the reactor, care must be taken that gelsare not formed which are subsequently difficult to disperse or dissolve.When adding the materials sequentially a preferred order is to first adddiluted sodium silicate, to next slowly add the dilute acid withstirring, to then slowly add the dilute sodium aluminate with continuedstirring and finally to add the seeds. Another preferred method to speedup the addition of the reactants is to feed the reactants in threestreams to a high speed mixer which forms a soft gel that can bedirectly fed to the crystallizing reactor. One stream contains sodiumsilicate and seeds, the second stream is a dilute acid stream and thethird stream is a dilute sodium aluminate stream.

In another embodiment after an initial heating of the reactant mixture,the liquid volume of the slurry can be reduced by decanting so that theensuing crystallization carried out for a relatively long period of timecan be done with a significantly reduced reactant volume such as a 2/3reduction in volume due to the removal of the extra liquid. The periodof initial heating can vary from a relatively short time such as about15 minutes to longer periods such as a day. Since the is carried out inall aqueous system, the mixture can be heated to temperatures of about100° C. without the need for pressurized equipment.

Using a reaction slurry which has a ratio of 16 SiO₂ to 1 Al₂ O₃, sodiumY type faujasites are obtained with SiO₂ /Al₂ O₃ ratios in the range ofabout 5.4 to about 6.0 depending on the reduced amount of active sodapresent. Using a reaction slurry which has a ratio of 9 SiO₂ to 1 Al₂O₃, sodium Y type faujasites are obtained with SiO₂ /Al₂ O₃ ratios inthe range of about 5.3 to about 5.8 depending on the reduced amount ofactive soda present.

The HSAY zeolite, like conventional NaY type zeolites, may be ionexchanged with solutions of rare earth salts or salts of other metals orammonium ion salts or combinations thereof to reduce the Na⁺ ion levelin the zeolite to make a thermally and hydrothermally stable promoterfor catalyst for treating petroleum fractions. Such ion exchange may becarried out by contacting the HSAY which has a % Na₂ O content assynthesized of about 10-15% with a water solution of any salt mentionedabove for one minute to 100 hours at temperatures of 0° C. to 100° C.,filtering t and washing the filter cake of zeolite. Repeated exchangeswith or without calcination of the exchanged zeolite may be done toreduce the Na⁺ ion content of the exchanged zeolite to as low as 0.1-5%Na₂ O depending upon the use to be made of the ion exchanged HSAYpromoter. These ion exchange procedures are well-known to those in thisart. Alternatively tne ion exchanging can be done after the HSAYpromoter has been made into a catalyst.

The high silica Y-zeolites made by this process are believed to beunique and this is characterized by their high degree of crystallinityas measured by the sharpness index of their NMR spectra to be discussedbelow and by the absence of occluded silica. As the SiO₂ /Al₂ O₃ ratioincreases there is a change in the nature of the chemical bondinginvolved. S. Ramdas et al. in their paper "Ordering of Aluminum andSilicon in Synthetic Faujasites", Nature, Vol. 292, July 16, 1981, atpages 228-230, report that zeolites may have five types of bonding ofsilicon to silicon or aluminum. These five types of bonding areexpressed in a notation which gives the number of aluminum atoms towhich the silicon is bonded through oxygen atoms. Each silicon is bondedto four oxygen atoms which in turn are each bonded to silicon oraluminum. The five types of bonding are Si(4 Al), Si(3 Al), Si(2 Al),Si(1 Al), and Si(0 Al). Thus, when silicon is bonded through the fouroxygen atoms to four aluminum atoms, the notation is Si(4 Al). See alsoKlinowski et al. "A Re-examination of Si,Al Ordering in Zeolites NaX andNaY" in J. Chem. Soc., Faraday Trans. 2, 78, 1025-1050 (1982).

The Ramdas et al. authors identified the five types of bonding by theuse of nuclear magnetic resonance. In Table 1 below is the distributionof the five types of bonds for a conventional NaY having a SiO₂ /Al₂ O₃ratio of 4.8 and the theoretical distribution for a HSAY-type materialwith a SiO₂ /Al₂ O₃ ratio of 6.0. For comparison, the table also liststhe idealized possible bonding for NaX type faujasite.

                  TABLE 1                                                         ______________________________________                                                         Type of Faujasite                                                             NaX    NaY    HSAY                                           ______________________________________                                        SiO.sub.2 /Al.sub.2 O.sub.3 Ratio                                                                2.4      4.8    6.0                                        Bonding Distribution (Idealized)                                              Si(4 Al)           16       0      0                                          Si(3 Al)           8        4      0                                          Si(2 Al)           0        16     16                                         Si(1 Al)           0        12     16                                         Si(0 Al)           2        2      4                                          ______________________________________                                    

The HSAY type material when made according to the present invention hasmore Si(1 Al) and Si(0 Al) bonds than conventional NaY zeolite less Si(3Al) bonds.

To measure these 5 types of bonding experimentally, a high resolution ²⁹Si NMR spectra is obtained as illustrated in FIG. 3 of the Ramdas et al.article and a computer-simulated curve is generated based on Gaussianpeak shapes. The area under the curves represents the relativepopulations of the five possible ordering modes.

This new analytical technique has also been used to determine the actualSiO₂ /Al₂ O₃ ratio in the crystal lattice, to identify occluded silicaif present, and to determine how well crystallized is the sample. Thetechnique uses Nuclear Magnetic Resonance (NMR) spectra of silicon-29which is an isotope of silicon present to the extent of 4.7% of all thesilicon atoms. The spectra are obtained a 79.45 MHz using magic anglespinning (MAS) which is a technique that greatly improves the resolutionof the NMR spectra. Two samples of HSAY labelled A and B made by thepresent invention and a commercial sample of NaY made by the processtaught by U.S. Pat. No. 3,639,099 were studied by this NMR techniqueusing MAS. Sample A was made by the process similar to the one set forthin Example 15 infra and Sample B was made by the process similar to theone set forth in Example 5. The NMR results showed the HSAY has a SiO₂/Al₂ O₃ ratio in the lattice of 5.6±0.4, that it had no occluded silica,and that it was very well crystallized. For the purposes of this case,the SiO₂ /Al₂ O₃ ratio will be determined by the conventional wetchemical method. The ratio as determined by NMR data has been givenbecause that value is strictly in terms of the amounts of silica andalumina in the crystalline structure. If there is any occluded silicapresent, it will not be included in the ratio determined by NMR.However, the NMR data is less precise as seen by the greateruncertainity for the values as reported in Table 2.

The MAS spectra were obtained at 79.45 MHz and referenced to tetramethylsilane using external HMDS (hexamethyl disiloxane) reference standardand assuming δHMDS=+6.7 p.p.m. with respect to TMS (tetramethylsilane).The spectra show five peaks characteristic of the five possibleenvironments possible for tetrahedral framework silicon in zeolitestructures as indicated on the spectra shown in FIG. 2. The scale inFIG. 2 is relative to TMS with the peak for TMS occuring at zero.

The spectra were deconvoluted into the separate components assuming thatthese were gaussian in nature. The complete assignment of the spectrumis given in Table 2 below together with the peak areas corrected for thesmall differential effects of sideband corrections. These smalldifferences in the shift values in the Table, compared to those on thespectrum, are due to the overlap between the peaks. The areas of eachpeak were adjusted so that the sum of the areas of the five peaksequalled 100. The width, w, of each peak at 1/2 peak height was alsocalculated. The Si[1 Al] and [0 Al] peaks of the HSAY sample in FIG. 2are sharper than the comparable peaks of the commercial NaY. Thissharpness can be defined mathematically as follows. If the area of theSi[2 Al] peak of each Y sample is used as a reference, a dimensionlesssharpness factor, S, for each peak is defined as ##EQU1## Then thesharpness index, S.I., of each peak other than the Si[2 Al] peak can bedefined as ##EQU2## These values for n=0 and 1 are set forth in Table 2below.

                  TABLE 2                                                         ______________________________________                                                    Commercial                                                                             HSAY                                                                 Sample   A          B                                             ______________________________________                                        SiO.sub.2 /Al.sub.2 O.sub.3 Ratio                                             By NMR        5.2 ± 0.4                                                                             5.6 ± 0.4                                                                             6.0 ±0.4                               By Chemical Analysis                                                                        5.0 ± 0.1                                                                             5.9 ± 0.1                                                                             6.0 ± 0.1                              Peak Types                                                                    Si(2 Al)                                                                      Area, A       36.0       34.5       33.7                                      Width, w, at 1/2 Height                                                                     3.1        3.35       3.2                                       Sharpness, A/w.sup.2                                                                        3.75       3.07       3.29                                      Si(1 Al)                                                                      Area, A       42.4       47.5       47.1                                      Width, w, at 1/2 Height                                                                     5.1        4.6        4.0                                       Sharpness, A/w.sup.2                                                                        1.63       2.24       2.94                                      Sharpness Index*                                                                            4.3        7.3        8.9                                       Si(0 Al)                                                                      Area, A       9.0        9.3        13.6                                      Width, w, at 1/2 Height                                                                     3.6        2.8        4.0                                       Sharpness, A/w.sup.2                                                                        0.69       1.19       0.85                                      Sharpness Index*                                                                            1.8        3.9        2.6                                       ______________________________________                                         *Sharpness Index = Sharpness of Si(1 Al) or Si(0 Al) peak ×             10/sharpness of Si(2 Al) peak.                                           

The data in Table 2 shows that the HSAY Si[1 Al] and Si[0 Al] peaks aremuch sharper than the same peaks of commercial NaY. The Si [1 Al] peakhas a sharpness index, S.I., of at least 6 and preferably at least 7while the Si [0 Al] peak has a S.I. of about 2.2 and preferably at least2.5. This sharpness of the [1 Al] and Si[0 Al] peaks or the present SiO₂/Al₂ O₃ ratio of the HSAY crystal lattice and the high degree ofcrystallinity of the HSAY.

As discussed above the magic angle NMR spectra can indicate if occludedsilica is present since there will be a characteristic, separate peakfor silica which is characterized by silicon atoms that are only bondedto oxygen atoms where the oxygen atoms are not further bonded to anyother atoms than silicon.

The presence of occluded silica can also be determined from unit celllength data. E. Dempsey et al., in the Journal of Physical Chemistry, 73(2), 387-390, (1969) compared the chemical analysis versus the unit celllength of various samples of NaX and NaY faujasite. They found that thelowest unit cell length among their samples of NaY was 24.66 A for a NaYwhich has a SiO₂ /Al₂ O₃ of 5.32 by cnemical analysis. However, theirplot of unit cell length versus number of aluminum atoms per unit cell(FIG. 1 in their paper) shows the lowest number of aluminu per unit cellis 53, corresponding to cell size or unit cell length of 24.665A where Ais Angstrom units. Although they examined several other NaY sampleswhere the chemical analysis indicated ratios of up to 5.83, none of theNaY samples had a unit cell smaller in length than 24.665A. Thereforethey suggest the high SiO₂ /Al₂ O₃ ratio samples contain amorphoussilica.

If a NaY sample contains amorphous silica intimately mixed with thecrystalline NaY, the apparent ratio by bulk chemical analysis will behigher than the actual ratio in the crystalline lattice. Their data,taken from their Table 1, has been plotted in FIG. 3 as unit cell sizeversus SiO₂ /Al₂ O₃ ratio. The open squares in FIG. 3 show their datafor well-crystallized samples of NaY; the unit cell length is inverselyproportional to the SiO₂ /Al₂ O₃ ratio. The triangles in FIG. 3demonstrate that the NaY samples which had a high ratio by chemicalanalysis do not show a progressive cell length shrinkage with increasingratio; these samples plotted as triangles probably contain occluded,amorphous silica. For these high ratio samples the cell length remainsat 24.66-24.67A even though the ratio increases from 5.4 to 5.8. Oneconcludes that the highest ratio in the crystalline lattice of the NaYsamples which they studied was about 5.3. The solid squares in FIG. 3are a plot of unit cell length versus SiO₂ /Al₃ O₃ ratio for highsilica/alumina ratio faujasite type NaY of the present invention. Thesolid squares appear to be generally an extension of the open squaresand demonstrate that HSAY samples of the present invention have a unitcell length proportional to the SiO₂ /Al₂ O₃ ratio obtained by chemicalanalysis. The solid squares continue down to a unit cell length of24.58A corresponding to a ratio of 6.0. Therefore the HSAY samples ofthe present invention not contain occluded, amorphous silica intimatelymixed with the faujasite. Moreover, the ratio obtained by chemicalanalysis of each sample is indeed the actual SiO₂ /Al₂ O₃ ratio in thecrystal lattice.

The unique high silica Y-zeolites made by the present invention with itshigh degree of crystallinity and absence of occluded silica is veryuseful as a catalyst material. These catalysts can be made usingprocedures set forth in the prior art. The HSAY is ion exchanged tolower the alkali metal content and to add stabilizing, catalyticallyactive ions. Typically, the HSAY is exchanged with rare earth ionsand/or ammonium and hydrogen ions. The HSAY may be ion exchanged eitherbefore or subsequent to inclusion in an inorganic oxide matrix.Furthermore, the ion exchanged HSAY may be calcined, i.e. heated attemperatures from about 200°; to 700° C. either prior to or afterinclusion in a catalyst matrix. Preferably, the HSAY, when employed as ahydrocarbon cracking catalyst, will possess alkali metal content,usually expressed as soda content, Na₂ O, of below about 6 percent byweight.

Conversion of the HSAY zeolite into usuable particulate catalyst isachieved by dispersing the finely divided HSAY zeolite into an inorganicoxide matrix. The inorganic oxide matrix may comprise or includesilica-alumina, alumina, silica sols or hydrogels, in combination withadditives such as clay, preferably kaolin, and other zeolites, such asZSM type zeolites.

The catalyst compositions may be prepared in accordance with theteachings of U.S. Pat. No. 3,957,689 which comprises combining a finelydivided zeolite and clay with an aqueous slurry which is spray dried andion exchanged to obtain a highly active hydrocarbon conversion catalyst.Furthermore, the catalyst preparation method may be as generally shownin Canadian 967,136 which involves combining zeolite and clay with anacid alumina sol binder. When it is desired to obtain a catalyst whichcontains a silica alumina hydrogel binder, the processing methods ofU.S. Pat. No. 3,912,619 may be utilized.

As indicated above, the HSAY zeolite is particularly resistant tohydrothermal deactivation conditions normally encountered duringregeneration of cracking catalysts. Regeneration involves hightemperature oxidation (burning) to remove accumulated carbon deposits attemperatures up to about 1000° C. Furthermore, it is found that thecatalysts contain the HSAY described herein are particularly resistantto the deactivation effects of contaminant metals such as nickel andvanadium which are rapidly deposited on the catalyst during the crackingof residual type hydrocarbons.

While the precise reason is not fully understood why the HSAY of thepresent invention and catalysts containing the HSAY described herein areparticularly active and stable, it is thought that this particularlyhigh degree of catalytic activity and stability after steam deactivationand in the presence of contaminant metals is due to its unique structureas discussed by S. Ramdas, et al. in their paper "Ordering Of AluminumAnd Silicon In Synthetic Faujasites", Nature, Vol. 292, July 16, 1981,pages 228-230.

During use, the catalytic cracking catalysts of the present inventionare combined with a hydrocarbon feedstock which may typically compriseresidual type petroleum hydrocarbon fractions that contain up to about1,000 parts per million nickel and vanadium and up to about 10 weightpercent sulfur, weight percent nitrogen. The cracking reaction snormally conducted at a temperature ranging from about 200° to 600° C.using a catalyst to oil ratio on the order of 1 to 30. During thecracking reaction the catalyst typically accumulates from about 0.5 to10 percent carbon, which is then oxidized during regeneration of thecatalyst. It is found that these catalysts are capable of sustainingdegrees of activity, even after accumulating up to about 4 percentcontaminating metals.

The catalysts may be advantageously combined with additional additivesor components such as platinum, which enhances the CO/SOxcharacteristics of tne catalyst. Preferably, platinum is included in theoverall catalyst composition in amounts of from about 2 to 10 parts permillion. Furthermore, the catalysts may be advantageously combined withSOx gettering components such as lanthanum/alumina composites thatcontain on the order of about 20 percent by weight lanthanum oxide.

Having described the basic aspects of our invention, the followingexamples are given to illustrate specific embodiments thereof.

EXAMPLE 1

This example illustrates the preparation of nucleation center seeds, asdisclosed in the McDaniel a U.S. Pat. No. 3,808,326.

A solution of 919 g. of sodium hydroxide in 2,000 ml. water was heatedto dissolve 156 g. alumina trihydrate (al₂ O₃.3H₂ O) and the solutionwas then cooled to room temperature and designated solution A. A secondsolution B was prepared by mixing 3,126 g. of 4.2° Be sodium silicate(weight ratio 1.0 Na₂ O: 3.22 SiO₂) into 1,555 ml. water. Then solutionA was mixed into solution B with rapid stirring. The mixture was aged atroom temperature for about 24 hours and then the slurry of nucleationcenters or seeds was ready for use.

EXAMPLES 2-5

These examples illustrate the of the high silica/alumina sodium Y typefaujasite where the seeded slurry has a silica/alumina ratio of 16:1.

The reactant solutions were prepared as follows. A diluted acid solutionwas prepared by adding the various amounts of concentrated sulfuric acidhaving a specific gravity of 1.84 as listed in Table 1 to 100 ml. waterand the mixture stirred well.

A dilute sodium aluminate solution was prepared by adding 91 g. ofsodium aluminate solution containing 17.2% Na₂ O by weight and 21.8% Al₂O₃ by weight to 214 g. water.

A diluted sodium silicate solution was prepared by pouring 648 g. of41.2° Be sodium silicate solution having a ratio of 1.0 Na₂ O:3.22 SiO₂in a 40 ounce blender cup of a Hamilton Beach Blender and adding 200 ml.water and the water was thoroughly mixed with the sodium silicate in theblender. While the blender was mixing, the diluted acid was added to thediluted silicate and followed by the addition of the diluted aluminate.Finally, 47 grams of seeds slurry was added to the mixture.

The slurry was poured into polypropylene bottles and capped loosely. Thebottles were heated in a water bath until the slurry reached atemperature of 85° C. at which time the bottles were transferred to anoven heated to 100° C. Samples of the slurry were taken from time totime by stirring the contents well and removin 50 of the slurry. Thesamples were filtered and washed to a pH of 10-10.5 and dried in an ovenat 100° C.

The percent crystallinity of each sample by powder X-ray diffractiontechniques was compared to a well crystallized, commercial sample of NaYfaujasite. The nitrogen surface area of the sample was measured, afterthe sample was degassed at 1000° F. for one hour, by the chromatographicmethod on a Perkin-Elmer-Shell 2,12D Sorptometer or by the BET method onan Aminco Adsorptomat.

The unit cell size of the cubic unit cell of HSAY in which all threeaxes have equal length (a=b=c) was measured as follows. Approximatelyone gram of HSAY powder which had been equilibrated in a dessicatorovernight in a 33% relative humidity atmosphere was mixed with about oneof silicon metal powder. The silicon served as an internal standard foran X-ray powder diffraction pattern made using copper radiation filteredthrough nickel foil. The diffraction pattern was recorded from about52°2θ to 60°2θ. The position in degrees 2θ of the reflection from 997plane (h=9, k=9, and 1=7) and from the 999 plane was measured. The firstappeared at about 54.0°-54.2°2θ and the second at about 58.7°-58.9°2θ.The silicon internal standard has a reflection at 56.12°2θtheoretically. The measured 2θ for the two HSAY planes was corrected bythe amount that the silicon peak varied from 56.12°. Then the unit cellwas calculated using the Bragg's Law equation: ##EQU3## where Γ is thecopper K.sub.α radiation wavelength of 1.54718 A. The unit cell was theaverage of the a from the 997 plane and from the 999 plane.

The resulting Nar type faujasite products, described in Table 3 below,which were crystallized from the slurries of Examples 2-5 had a highSiO₂ -Al₂ O₃ ratio and especially in Examples 4 and 5.

                                      TABLE 3                                     __________________________________________________________________________    Synthesis of High Silica-Alumina Ratio NaY Faujasite from                     "16 SiO.sub.2 :1.0 Al.sub.2 O.sub.3 " Seeded Slurries                                   Conc.                  SiO.sub.2 /Al.sub.2 O.sub.3                       Moles                                                                              Sulfuric    %    Nitrogen                                                                            Ratio by                                                                            Unit                                   Example                                                                            Na.sub.2 O:1.0                                                                     Acid Hours at                                                                             Crystal-                                                                           Surface                                                                             Chemical                                                                            Cell                                   No.  Al.sub.2 O.sub.3                                                                   g.   100 ± 1° C.                                                                linity                                                                             Area,m.sup.2 /g                                                                     Analysis                                                                            Size, Å                            __________________________________________________________________________    2    5.6  16.7 36     104  854   5.4   24.61                                  3    5.4  20.9 40     102  838   5.7   24.60                                  4    5.2  24.9 64      97  853   5.9   24.59                                  5    5.0  29.1 108     99  802   6.0   24.58                                  __________________________________________________________________________

Examples 6-9

These examples illustrate the production of the high silica/aluminasodium Y type faujasite where the seeded slurry has a silica/aluminaratio of 9:1.

The sodium silicate and sodium aluminate solutions had the sameconcentrations as in Examples 2-5. The sodium silicate and 1/2 of thewater were blended in the 40 ounce blender cup of a Hamilton Beachblender. The seeds prepared according to Example 1 were added in theamounts listed in Table 4 and blended. The sodium aluminate solution wasmixed with the other 1/2 of the water. The mixture became very viscous,to the point that the mixture gels, and the blender was turned off. Thegel was carefully and completely scraped out of the blender cup,transferred to the bowl of a Hobart kitchen mixer. After turning on theHobart mixer the remainder of the sodium aluminate solution was slowlyadded. Then the aluminum sulfate (alum) solution which had 7.8% Al₂ O₃was slowly added while mixing was continued. The thick, pasty gel wasput into 250 ml. or 500 ml. polypropylene bottles and capped loosely.The remaining heating and analysis procedure was the same as Examples2-5. The resulting NaY type faujasite products, described in Tables 4and 5 were crystallized from the slurries of Examples 6-9, and they hada high SiO₂ /Al₂ O₃ ratio, especially Examples 8 and 9.

                  TABLE 4                                                         ______________________________________                                        Synthesis of High Silica-Alumina Ratio NaY Faujasite from                     "9 SiO.sub.2 :1.0 Al.sub.2 O.sub.3 " Seeded Slurries                          Reactants                                                                     Ex-                   Sodium                                                  am-  Moles            Alumin-      Sodium                                                                              Al.sub.2 (SO.sub.4).sub.3            ple  Na.sub.2 O:1.0                                                                         Seeds   ate Soln.                                                                            Water Silicate                                                                            Soln.                                No.  Al.sub.2 O.sub.3                                                                       g.      g.     g.    g.    g.                                   ______________________________________                                        6    3.0      194     140    235   860   230                                  7    2.8      194     129    220   860   260                                  8    2.6      175     106    184   774   262                                  9    2.4      175      96    169   774   289                                  ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                        Synthesis of High Silica-Alumina Ratio NaY Faujasite from                     "9 SiO.sub.2 :1.0 Al.sub.2 O.sub.3 " Seeded Slurries                          Reactant Time and Product Analyses                                            Ex-                               SiO.sub.2 /Al.sub.2 O.sub.3                                                           Unit                                am-             %        Nitrogen Ratio by                                                                              Cell                                ple  Hours at   Crystal- Surface  Chemical                                                                              Size,                               No.  100 ± 1° C.                                                                    linity   Area m..sup.2 /g.                                                                      Analysis                                                                              a                                   ______________________________________                                        6    12         108      859      5.3     24.64                               7    20         109      884      5.4     24.62                               8    36         104      910      5.6     24.61                               9    60         103      897      5.8     24.60                               ______________________________________                                    

Example 10

This example illustrates the synthesis using a reduced volume of slurryafter an initial heated reaction so that the crystallization step whichis carried out for a relatively long period of time can be done with asignificant reduction in the volume required.

A 16:1 silica to alumina slurry was prepared having a compositionaccording to Example 5. The slurry was heated in a bottle withoutstirring for 24 hours at 100° C. During this period tne solids settledto the bottom of the bottle. After the 24-hour heating period the motherliquor was decanted off so there was about 2/3 reduction in volume. Theremaining solids surrounded by mother liquor were then heated at 100° C.for 131 hours to obtain a good product having a surface area of 897 m²/g., a crystallinity of 94% with a unit cell s:ze of 24.59 Angstromunits. This corresponds to a SiO₂ /Al₂ O₃ ratio of 5.9. as seen in Table3.

Example 11

This example illustrates the production of the Y zeolite using a reducedvolume of slurry with a shorter period of initial heating.

A procedure similar to that used in Example 10 was followed except thatinstead of heating the slurry for 24 hours at 100° C. it was only heatedat 100° C. for 15 minutes. The solids were filtered on a Buchner filter.The solids were then returned to the bottle and only enough motherliquor was added to just cover the solids. Since these solids werefluffier than those produced in Example 10, a greater amount of liquorwas required. The volume reduction was about 55-60% which is slightlyless than the volume reduction in Example 10.

After crystallizing the mixture at 100° C. for 144 hours the product had107% crystallinity, the unit cell a dimension was 24.61 Angstrom unitsand the wet chemical analysis of the SiO₂ /Al₂ O₃ was 5.8.

This example also shows obtaining a good product at reducedcrystallization volumes with the recovery of excess mother liquor whichcan be recycled or used for other purposes.

Example 12

This example also illustrates the synthesis using a reduced volume ofslurry with a slightly longer initial period of heating.

In this example the exact procedure of Example 11 was followed exceptthat instead of initially heating the slurry at 100° C. for 15 minutes,it was heated for 1 hour. The solids were filtered as in the procedureof Example 11 and just enough mother liquor was added to cover thesolids. After heating at 100° C. for 93 hours the percent crystallinitywas 109%, the unit cell a dimension was 24.60, and the SiO₂ /Al₂ O₃ratio by wet chemical analysis was 5.8.

Example 13

This example illustrates the use of alum gelled mother liquor, AGML, tosupply some of the silica and alumina reactant materials when using aslurry with a 16:1 silica/alumina ratio.

From a previous production of a sodium Y zeolite made by the processaccording to the McDaniel et al. U.S. Pat. No. 3,639,099, the typicalfiltrate of mother liquor filtered off from the fully crystallized NaYbatch contains:

4.9% SiO₂ and 4.0% Na₂ O.

Aluminum sulfate (alum) solution is added and the silica alumina gel,AGML, precipitates and is recovered by filtration. The gel contains:

12.6% SiO₂

3.4% Na₂ O

2.8% Al₂ O₃

2.6% SO₃, and

balance water

A slurry for the synthesis of a high silica faujasite according to thepresent invention was made by mixing in a blender 300 grams AGML with200 grams water and 517 grams sodium silicate solution (41.2° Becontaining silica and soda in the ratio of 3.22 SiO₂ :1.0 Na₂ O). Then54 grams of sodium aluminate solution (18.2% Na₂ O; 21.4% Al₂ O₃) whichwas diluted with 185 grams water was added and mixed well. Finally 47grams of a seed slurry as made in Example 1 was mixed in the blender.The effective slurry ratio was 5.2 Na₂ O: 1.0 Al₂ O₃ :16 SiO₂ :280 H₂ O.

The completely mixed slurry was put into a 1.0 liter polypropylenebottle which was placed into an oven at 100°±1° C. After 61 hours theslurry made a well crystallized NaY faujasite, of the high silica typeaccording to the present invention, having a nitrogen surface area of952 m² /g. This was measured on a Digisorb instrument manufactured byMicromeritics Inc., Norcross, Ga. The HSAY faujasite had the followingchemical analysis

10.7% Na₂ O: 19.8% Al₂ O₃ : 69.5% SiO₂

with a SiO₂ /Al₂ O₃ ratio=6.0 and a crystallinity of 102%.

This is an efficient use of a waste stream.

Example 14

This example illustrates the use of alum gelled mother liquor to supplysome of the silica and alumina reactant materials when using a slurrywith a 9:1 silica/alumina ratio.

1,080 grams of AGML made as described in Example 13 was put into thebowl of a mixer and 319 grams 41.2° Be silicate was added and mixed inthe mixer. Then 69 grams of sodium aluminate solution was slowly addedand mixed. The slurry became stiff, but softened after mixing for 1-2minutes. Finally, 93 grams of seed slurry made according to Example 1,were added. The slurry was transferred to a 1.0 liter polypropylenebottle and heated in an oven at 100°±1° C. The effective slurry oxideratio was 2.4 Na₂ O: 1.0 Al₂ O₃ : 9 SiO₂ : 140 H₂ O.

After 44 hours a high silica Y faujasite crystallized which had anitrogen surface area of 937 m² /g and a good crystallinity whichmeasured as 101% when compared to a commercial NaY standard. Chemicalanalysis of the composition on a dry basis was as follows:

10.9% Na₂ O: 20.4% Al₂ O₃ : 68.7% SiO₂

The SiO₂ /Al₂ O₃ ratio was 5.7.

Example 15

This example demonstrates the scale-up of the process to a 15 gallonbatch which yields nearly 6.0 kg. of dry product.

40.0 kg. of commercial sodium silicate (Philadelphia Quartz "N" Brand,40.8 Be gravity) was placed into a mixing tank and diluted with 11.5 kg.water. The mixer was turned on and kept on throughout the addition ofchemicals. A solution of 1,531 grams concentrated sulfuric (gravity1.84) diluted with 11.4 kg. water was very slowly added over a 15 minuteperiod. Mixing was continued for 1/2 hour more.

Then a diluted solution of sodium aluminate made from 5,226 gramsconcentrated sodium aluminate solution (18.2% Na₂ O; 21.4% Al₂ O₃) mixedwith 5.9 kg. water was slowly added over a 1/2 hour.

Finally, 2,631 grams seeds or nucleation centers (described inExample 1) was added. The slurry was pumped to a 20 gallonsteam-jacketed reaction tank and heated to 100°±1° C. to crystallize theNaY. The slurry was sampled from time to time to monitor the progress ofthe crystallization. After 105 hours at temperature the run was stopped.The slurry was filtered and the filter cake washed free of excess motherliquor.

The product was a well crystallized HSAY with a SiO₂ /Al₂ O₃ ratio of6.0 and a crystallinity of 96%.

Example 16

This example demonstrates both scale-up to a 15 gallon slurry batch andthe use of another type of sodium silicate. The mixing andcrystallizaton procedures were the same as in Example 13.

Mixed together were 41.5 kg. Diamond Shamrock DS 34 sodium silicate(25.6% SiO₂ ; 6.6% Na₂ O) and 14.6 kg. water. A solution of 696 gramsconcentrated sulfuric acid diluted with 4.5 kg. water was added. The5,253 grams of sodium aluminate of the same concentration as in Example13 diluted with 4.5 kg. water was added. Lastly, 2,192 grams seeds wereadded of the type described in Example 1.

The crystallization at 100°±1° C. yielded HSAY with a SiO₂ /Al₂ O₃ ratioof 5.8 and a crystallinity of 104% in 72 hours.

Example 17

This example illustrates the production of a large batch using thesimultaneous addition of the reactants.

Three solutions were prepared. In a first tank was added 36.7 kg. of41.0° Be sodium silicate, 12.2 kg. water and 2,633 g. of seeds of thetype described in Example 1. The materials were mixed and heated to 60°C.

In a second tank a dilute acid solution was prepared by mixing 1,537 g.of concentrated sulfuric acid with 9,100 g. water.

In a third tank a dilute sodium aluminate solution was prepared bymixing 5,232 g. of sodium aluminate (18.2% Na₂ O and 21.4% Al₂ O₃) with6,800 g. water.

The three tanks were connected by lines to a reactor having a high speedmixing pump and the line from the first tank was opened first. After thethree streams were mixed by the high speed mixing pump they formed asoft gel which was fed to a reactor with further stirring. The reactorwas closed and the gel was heated gradually to 100° C. while stirringcontinued. After the 100° C. temperature was reached, the stirrer wasturned off and the mixture was maintained at this temperature for 70-80hours to crystallize the HSAY. The slurry was then quenched with coldwater and filtered with subsequent washings with hot water. The materialwas dried and yielded 6 kg. of well-crystallized HSAY having a SiO₂ /Al₂O₃ ratio of 5.9 and a percent crystallinity as 103%. The unit cell sizewas 24.60 Angstrom units and the nitrogen surface area measured by theBET method using a Micromeritics Digisorb was 875 m.² /g. The chemicalanalysis was 11.0% Na₂ O, 19.6% Al₂ O₃ and 68.4% SiO₂.

Example 18

HSAY zeolite was rare earth exchanged and calcined to obtain a "CREHSAY"that comprised 14.0 percent RE₂ O₃, 2.45 percent Na₂ O and a silica to alumin ratio of 5.9:1.0 by the following procedure.

A 4,444 g portion of HSAY filter cake (45% solids) obtained in Example17 was slurried in 9 l of deionized water. The HSAY slurry was thenblended into a solution of 4,444 ml commercial mixed rare earth chloridesolution (61% RECl₃.6H₂ O by weight) diluted with 7.5 l of deionizedwater. The resulting mixture was heated to 90° C.-100° C. and held atthat temperature for one hour. The slurry was filtered and the filtercake was washed twice with 3 l of boiling deionized water. The washedfilter cake was slurried into a solution of 4,444 ml commercial rareearth solution diluted with 16.5 liters of deionized water. The mixturewas again heated to 90°-100° C. and held at temperature for one hour.Then the slurry was filtered and resulting filter cake was washed threetimes with 3 l of boiling deionized water. The filter cake was then ovendried at 150° C. for 4- 8 hours. Finally, the dried zeolite was calcinedat 538° C. for three hours. The product CREHSAY had the followingproperties:

    ______________________________________                                        Loss on Ignition (LOI)  2.1 wt. %                                             RE.sub.2 O.sub.3       14.0 wt. %                                             Na.sub.2 O              2.5 wt. %                                             Ratio SiO.sub.2 /Al.sub.2 O.sub.3                                                                     5.9 ± 0.1                                          Nitrogen Surface Area  768 m.sup.2 /gm                                        (by BET method)                                                               ______________________________________                                    

Example 19

(a) The CREHSAY of Example 18 was used to prepare a FCC catalystaccording to the teachings of U.S. Pat. No. 3,957,689. Anacid-alum-silica sol was made by mixing two solutions A and B through ahigh speed mixer. Solution A was 11.5 kg of 12.5% SiO₂ sodium silicate(Na₂ O: 3.2 SiO₂). Solution B was 3.60 l of a solution made from 20weight percent sulfuric acid (2.2 l) and dilute aluminum sulfatesolution, 77 g Al₂ O₃ per liter (1.4 liters). The ratio of the flows ofsolutions A and B through the mixer is approximately 1.5 l solution A to0.5 l solution B. The ratio of the flows is adjusted to produce anacid-alum-silica sol having a pH of 2.9-3.2. To 14.4 kg ofacid-alum-silica sol is added a slurry composed of 2,860 g kaolin clayand 2,145 g CREHSAY from Example 18 mixed into 6 l water. The mixture ofthe acid-alum-silica sol and the slurry of CREHASY and kaolin in waterwas blended and spray dried using an inlet temperature of 316° C. and anoutlet temperature of 149° C. A 3,000 g portion of the spray driedproduct was slurried in 11.3 l of water at 60°-71° C. and filtered. Thefilter cake was washed three times with 3 l of 3 percent ammoniumsulfate solution. Then the cake was reslurried in 9 l of hot water,filtered, and, finally, rinsed three times with 3 l of hot water. Thecatalyst was then oven dried at 149° C.

(b) A catalyst having the same proportions of ingredients was made inthe same manner from calcined rare earth exchanged conventional NaYhaving a silica to alumina ratio of about 4.9±0.1

The results of comparison tests are shown below in Table 6. Themicroactivity test used a modification of the test procedure publishedby F. G. Ciapetta and D. S. Henderson entitled "Microactivity Test ForCracking Catalysts", Oil And Gas Journal, Vol. 65, pages 88-93, Oct. 16,1967. Microactivity tests are routinely used in the petroleum industryto evaluate cracking catalysts in the laboratory. The petroleum fractionwhich was cracked over these catalysts was a West Texas Heavy Gas Oil(WTHGO) using the following test conditions:

Temperature 499° C.;

Weight Hourly Space Velocity (WHSV) 16;

Catalyst to oil ratio 3.

The WTHGO (1.67 g) is passed through 5.0 g of catalyst in 1.3 minutes.The products are collected and the percent conversion of gas oil intohydrogen, light gases, gasolene range hydrocarbons, etc. are determinedby gas chromatography.

The catalysts were impregnated with Ni and V as naphthenates dissolvedin WTHGO; next the hydrocarbons were burned off by slowly raising thetemperature to 677° C. Then the metals impregnated catalysts were steamdeactivated by the S-13.5 procedure before testing for crackingmicroactivity.

                  TABLE 6                                                         ______________________________________                                        Catalyst Composition (wt. %)                                                                   Example 19(b)                                                                             Example 19(a)                                    ______________________________________                                        Zeolite          35          35                                               SiO.sub.2        24          24                                               Clay             41          41                                               Na.sub.2 O       0.49        0.37                                             RE.sub.2 O.sub.3 4.94        5.08                                             Al.sub.2 O.sub.3 26.5        26.0                                             ______________________________________                                        Microactivity (Vol. % Conv.) After Indicated Deactivation                     ______________________________________                                        S-13.5.sup.(1)                                                                0% Metals        82          86                                               1% (Ni + V).sup.(2)                                                                            53          74                                               1500.sup.(3)     81          80                                               1550.sup.(4)     20          64                                               ______________________________________                                        Partial Chemical Analysis of Zeolite                                                               CREY      HSACREY                                        ______________________________________                                        SiO.sub.2 /Al.sub.2 O.sub.3 (Ratio)                                                                4.9 ± 0.1                                                                            5.8 ± 0.1                                   RE.sub.2 O.sub.3 (Wt. %)                                                                           15.0 ± 1                                                                             14.0 ± 1                                    Na.sub.2 O (Wt. %)   3.2 ± 0.2                                                                            2.4 ± 0.2                                   ______________________________________                                         .sup.(1) Steam deactivation: 8 hours at 732° C., 100% steam at 1.1     kg/cm.sup.2 gauge pressure.                                                   ##STR1##                                                                      .sup.(3) Steam deactivation: 5 hours at 816° C., 100% steam at 0       kg/cm.sup.2 gauge pressure.                                                   .sup.(4) Steam deactivation: 5 hours at 843° C., 100% steam at 0       kg/cm.sup.2 gauge pressure.                                              

Example 20

(a) A slurry was made from 2,576 g HSAY filter cake (45% solids) from abatch of HSAY synthesized as in Example 17 and 4,186 g of kaolin in 8.0l of water. This slurry was thoroughly blended with 13.8 kg ofacid-alum-silica sol, the preparation of which was described in Example19. The mixture was spray dried using the conditions described inExample 19. The then spray dried material was washed with water and ionexchanged with mixed rare earth chloride solution as follows: A 3,000 gportion of spray dried material was slurried in 11.3 l of hot deionizedwater at 60°-71° C. and filtered. The filter cake was rinsed three timeswith 3 l of hot water. Then the cake was reslurried in 9 l of hot waterand filtered again. The cake was rinsed three times with 3 l portions ofhot water. The filter cake was next reslurried in 10 l of hot water and215 ml of mixed rare earth chloride solution (60 wt. % RECl₃.6H₂ O) weremixed into the slurry. The slurry was gently stirred for 20 minutes andkept at a temperature of 60°-71° C., and the pH was kept at 4.7-5.2.Lastly the slurry was filtered again and rinsed with three 3 l portionsof hot water.

(b) A similar catalyst was prepared using a conventional NaY zeolitethat has a SiO₂ /Al₂ O₃ ratio of about 4.9±0.1

The finished catalyst was then oven dried at 149° C. The finishedcatalyst made from HSAY was compared in the tests given below in Table 7with the catalyst made in a similar manner from conventional NaY. WestTexas Heavy Gas Oil was cracked in the microactivity test using the testconditions given in Example 19.

                  TABLE 7                                                         ______________________________________                                                       Example 20(b)                                                                           Example 20(a)                                        ______________________________________                                        Catalyst Composition (wt. %)                                                  Zeolite          17          17                                               SiO.sub.2        23          23                                               Clay             60          60                                               Na.sub.2 O       0.74        0.70                                             RE.sub.2 O.sub.3 3.68        3.83                                             SiO.sub.2 /Al.sub.2 O.sub.3 ratio of zeolite                                                   4.9 ± 0.1                                                                              5.8 ± 0.1                                     Microactivity (Vol. % Conv.)                                                  S-13.5 Deactivation                                                           As Is            73          82                                               0% Metals        68          72                                               0.5% (Ni + V)    28          54                                               1500 Deactivation.sup.(1)                                                                      48          62                                               ______________________________________                                         .sup.(1) Steam deactivation: 5 hours at 816° C., 100% steam at 0       kg/cm.sup.2 gauge pressure.                                              

For each of the catalysts described above in Examples 19 and 20 thecatalyst made with the HSAY type zeolite demonstrates better resistanceto hydrothermal deactivation than the same formulation of catalyst madewith an equal amount of conventional Y type zeolite. The two catalystsin Examples 19 and 20 made with HSAY also show greater resistance todeactivation by vanadium and nickel contamination (heavy metalspoisoning) than the equivalent catalysts made from conventional Y typezeolite.

The above catalyst examples clearly indicate that valuable crackingcatalysts may be obtained using the HSAY according to the presentinvention.

It is understood that the foregoing detailed description is given merelyby way of illustration and that many variations may be made thereinwithout departing from the spirit of the invention.

What is claimed is:
 1. A process of producing zeolite Y having a formulain terms of moles of oxides as

    0.9±0.2 Na.sub.2 O: Al.sub.2 O.sub.3 : wSiO.sub.2 : xH.sub.2 O

where w is a value greater than 5.0 and x may have a value of up toabout 9, comprising (a) forming a reaction slurry by mixinga source ofalumina other than metakaolin or kaolin; a source of silica selectedfrom the group consisting of sodium silicate, silica gel, silicic acidand mixtures thereof; a source of soda; a source of seeds or nucleationcenters; and a further reactant which is either(I) a controller ofactive soda selected from the group consisting of an acid, a solution ofa salt obtained from aluminum and an acid, and mixtures thereof; (II) acombination source of reactive silica and alumina which is low in activesoda; or (III) a mixture of (I) and (II);sources and said furtherreactant being selected to control the active soda concentration in thereaction slurry, as measured by the ratio of active moles of Na₂ O toone mole of Al₂ O₃, below the value given by line A in FIG. 1 for thecorresponding ratio of moles of silica to one mole of alumina in thereaction slurry, said line A being based on at least the followingpoints for ratios in the synthesis slurry

    ______________________________________                                        SiO.sub.2 :Al.sub.2 O.sub.3                                                                 Na.sub.2 O:Al.sub.2 O.sub.3                                     Ratio         Ratio                                                           ______________________________________                                        16:1          6.6:1                                                           9:1           3.1:1                                                           6:1           1.8:1                                                           ______________________________________                                    

and (b) heating the reaction slurry product of step (a) to crystallizezeolite Y.
 2. A process of producing zeolite Y according to claim 1,wherein w in the formula has a value of equal to or greater than about5.8 by maintaining the concentration of the active sodium in thereaction slurry at or below the value given by line B in FIG. 1 for thecorresponding ratio of moles of silica to moles of alumina in thereaction slurry, said line B being based on at least the followingpoints for ratios in the synthesis slurry

    ______________________________________                                        SiO.sub.2 :Al.sub.2 O.sub.3                                                                 Na.sub.2 O:Al.sub.2 O.sub.3                                     Ratio         Ratio                                                           ______________________________________                                        16:1          5.0                                                              9:1          2.4                                                             ______________________________________                                    


3. A process according to claim 1, wherein the acid in the controller ofactive soda is sulfuric acid.
 4. A process according to claim 1, whereinthe salt obtained from aluminum and an acid in the controller of activesoda is aluminum sulfate.
 5. A process according to claim 1, wherein thecombination source of silica and alumina is an aluminum salt gelledmother liquor.
 6. A process according to claim 5, wherein the aluminumsalt which gels the mother liquor is selected from the group consistingof aluminum sulfate, aluminum chloride, aluminum nitrate, and mixturesthereof.
 7. A process according to claim 6, wherein the aluminum salt isaluminum sulfate.
 8. A process according to claim 1, wherein thereaction slurry is heated and the excess mother liquor is decantedbefore the reaction product is crystallized.
 9. A process according toclaim 1, wherein the source of alumina, the source of silica, and thecontroller of active soda are fed by separate streams to a mixer withthe source of seeds or nucleation centers added to one of the streams toform the reaction slurry which is then heated in step (b).
 10. A processaccording to claim 9, wherein said separate streams are fed to the mixersimultaneously.
 11. The high silica zeolite Y made by the process ofclaim 1 and having a unit cell size of 24.64 or less.
 12. The highsilica zeloite Y made by the process of claim 2 and having a unit cellsize of 24.64 or less.
 13. The high silica zeolite Y made by the processof claim 3 and having a unit cell size of 24.64 or less.
 14. The highsilica zeolite Y made by the process of claim 4 and having a unit cellsize of 24.64 or less.
 15. The high silica zeolite Y made by the processof claim 5 and having a unit cell size of 24.64 or less.
 16. The highsilica zeolite Y made by the process of claim 6 and having a unit cellsize of 24.64 or less.
 17. The high silica zeolite Y made by the processof claim 7 and having a unit cell size of 24.64 or less.
 18. The highsilica zeolite Y made by the process of claim 8 and having a unit cellsize of 24.64 or less.
 19. The high silica zeolite Y made by the processof claim 9 and having a unit cell size of 24.64 or less.
 20. The highsilica zeolite Y made by the process of claim 10 and having a unit cellsize of 24.64 or less.
 21. A high silica, well crystallized zeolite Ywith little occluded amorphous silica having a formula as crystallizedin terms of moles of oxides as

    0.9±0.2 Na.sub.2 O: Al.sub.2 O.sub.3 : wSiO.sub.2 : H.sub.2 O

where w is a value greater than 5.0 in the crystalline lattice of thezeolite Y, x has a value up to about 9, and having a sharpness index,S.I., of at least 6 for the Si[1Al] peak and at least about 2.2 for theSi[0 Al] peak based on the sharpness index formula ##EQU4## where n is 0or 1 and where the sharpness, S, is defined as ##EQU5## where the peakarea and width are measured on deconvoluted magic angle spinning nuclearmagnetic resonance peak spectra of silicon-29, said zeolite Y having aunit cell size of 24.64 or less and having no impurities from metakaolinor kaolin.
 22. A high silica zeolite Y according to claim 21, whereinthe sharpness index is at least 7 for the Si[1 Al] peak and at least 2.5for the Si[0 Al] peak.
 23. A high silica zeolite Y according to claim21, wherein w has a value greater than 5.4.
 24. A high silica zeolite Yaccording to claim 21, wherein w has a value greater than 5.8.